Read lines from a file inside a zip archive using Haskell's zip-conduit

Question

As the title says, I'd like to be able to read lines from a file that is inside a zip archive, using zip-conduit (the zip files I'm dealing with are very big, so I need to be able to do this in constant memory). I grok the very basic idea of conduits, but have never used them in anger, and am feeling quite stuck as to where to start. I've read the conduits tutorial, but I'm having trouble matching that up with my problem.

The zip-conduit documentation says one can source from a zip archive via something like the following:

import qualified Data.Conduit.Binary as CB
import Codec.Archive.Zip

withArchive archivePath $ do
    name:_ <- entryNames
    sourceEntry name $ CB.sinkFile name

I presume what I need to do is write something in place of CB.sinkFile. Data.Conduit.Text has a lines function — could this be used in some way to get the lines out of the file?

I would really appreciate a simple example, say using putStrLn to write out the lines of a simple text file that is archived inside a zip file. Thanks in advance.

Answer 1

Michael's answer but with zip-conduit:

import           Control.Monad.IO.Class (liftIO)
import           Data.Conduit
import qualified Data.Conduit.List as CL
import qualified Data.Conduit.Text as CT
import           Codec.Archive.Zip

main :: IO ()
main = withArchive "input.zip" $ do
  n:_ <- entryNames
  sourceEntry n
     $ CT.decode CT.utf8
    =$ CT.lines
    =$ CL.mapM_ (\t -> liftIO $ putStrLn $ "Got a line: " ++ show t)

Answer 2

Here's a simple example:

import           Control.Monad.IO.Class (liftIO)
import           Data.Conduit
import qualified Data.Conduit.Binary    as CB
import qualified Data.Conduit.List      as CL
import qualified Data.Conduit.Text      as CT

main :: IO ()
main = runResourceT
     $ CB.sourceFile "input.txt"
    $$ CT.decode CT.utf8
    =$ CT.lines
    =$ CL.mapM_ (\t -> liftIO $ putStrLn $ "Got a line: " ++ show t)

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